scholarly journals Reconstructing glacier-based climates of LGM Europe and Russia – Part 3: Comparison with previous climate reconstructions

2008 ◽  
Vol 4 (4) ◽  
pp. 265-280 ◽  
Author(s):  
R. Allen ◽  
M. J. Siegert ◽  
A. J. Payne

Abstract. Understanding past climates using GCM models is critical to confidently predicting future climate change. Although previous analysis of GCM simulations have shown them to under calculate European glacial temperature anomalies (the difference between modern and glacial temperatures) such analyses have focused primarily on results from glacial simulations alone. Here we compare glacial maximum GCM results with the palaeoenvironment derived from glacier-climate modelling. The comparison confirms that GCM anomalies are not large enough, and that this is due to modern conditions that are modelled too cold and glacial temperatures that are too warm. The result is that GCM results, if applied to a glacier mass balance model, over predict the extent of glaciers today, and under calculate their extent at the last glacial (as depicted in glacial geological reconstructions). Effects such as seasonality and model parameterisation change the magnitude of the under calculation but still fail to match expected glacial conditions.

2007 ◽  
Vol 3 (5) ◽  
pp. 1199-1233 ◽  
Author(s):  
R. Allen ◽  
M. J. Siegert ◽  
A. J. Payne

Abstract. Understanding past climates using GCM models is critical to confidently predicting future climate change. Although previous analysis of GCM simulations have shown them to under predicted European glacial temperature anomalies (the difference between modern and glacial temperatures) such analyses have focused primarily on results from glacial simulations alone. Here we compare glacial maximum GCM results with the palaeoenvironment derived from glacier-climate modelling. The comparison confirms that GCM anomalies are under predicted, and that this is due to modern conditions that are modelled too cold and glacial temperatures that are too warm. The result is that CGM results, if applied to a glacier mass balance model, over predict the extent of glaciers today, and under predict their extent at the last glacial (as depicted in glacial geological reconstructions). Effects such as seasonality and model parameterisation change the magnitude of the under prediction but still fail to match expected glacial conditions.


2010 ◽  
Vol 23 (6) ◽  
pp. 1589-1606 ◽  
Author(s):  
Sven Kotlarski ◽  
Frank Paul ◽  
Daniela Jacob

Abstract A coupling interface between the regional climate model REMO and a distributed glacier mass balance model is presented in a series of two papers. The first part describes and evaluates the reanalysis-driven regional climate simulation that is used to force a mass balance model for two glaciers of the Swiss mass balance network. The detailed validation of near-surface air temperature, precipitation, and global radiation for the European Alps shows that the basic spatial and temporal patterns of all three parameters are reproduced by REMO. Compared to the Climatic Research Unit (CRU) dataset, the Alpine mean temperature is underestimated by 0.34°C. Annual precipitation shows a positive bias of 17% (30%) with respect to the uncorrected gridded ALP-IMP (CRU) dataset. A number of important and systematic model biases arise in high-elevation regions, namely, a negative temperature bias in winter, a bias of seasonal precipitation (positive or negative, depending on gridbox altitude and season), and an underestimation of springtime and overestimation of summertime global radiation. These can be expected to have a strong effect on the simulated glacier mass balance. It is recommended to account for these shortcomings by applying correction procedures before using the RCM output for subsequent mass balance modeling. Despite the obvious model deficiencies in high-elevation regions, the new interface broadens the scope of application of glacier mass balance models and will allow for a straightforward assessment of future climate change impacts.


2005 ◽  
Vol 42 ◽  
pp. 277-283 ◽  
Author(s):  
Andrew Wright ◽  
Jemma Wadham ◽  
Martin Siegert ◽  
Adrian Luckman ◽  
Jack Kohler

AbstractA surface-energy/mass-balance model with an explicit calculation of meltwater refreezing and superimposed ice formation is applied to midre Lovénbreen, Spitsbergen, Svalbard. The model is run with meteorological measurements to represent the present climate, and run with scenarios taken from global climate model predictions based on the IS92a emissions scenario to represent future climates. Model results indicate that superimposed ice accounts for on average 37% of the total net accumulation under present conditions. The model is found to be highly sensitive to changes in the mean annual air temperature and much less sensitive to changes in the total annual precipitation. A 0.5˚C decade–1 temperature increase is predicted to cause an average mass-balance change of –0.43 ma–1, while a 2% decade–1 increase in precipitation will result in only a +0.02 ma–1 change in mass balance. An increase in temperature results in a significant decrease in the size of the accumulation area at midre Lovénbreen and hence a similar decrease in the net volume of superimposed ice. The model predicts, however, that the relative importance of superimposed ice will increase to account for >50% of the total accumulation by 2050. The results show that the refreezing of meltwater and in particular the formation of superimposed ice make an important positive contribution to the mass balance of midre Lovénbreen under present conditions and will play a vital future role in slowing down the response of glacier mass balance to climate change.


2013 ◽  
Vol 17 (9) ◽  
pp. 3661-3677 ◽  
Author(s):  
A. F. Lutz ◽  
W. W. Immerzeel ◽  
A. Gobiet ◽  
F. Pellicciotti ◽  
M. F. P. Bierkens

Abstract. Central Asian water resources largely depend on melt water generated in the Pamir and Tien Shan mountain ranges. To estimate future water availability in this region, it is necessary to use climate projections to estimate the future glacier extent and volume. In this study, we evaluate the impact of uncertainty in climate change projections on the future glacier extent in the Amu and Syr Darya river basins. To this end we use the latest climate change projections generated for the upcoming IPCC report (CMIP5) and, for comparison, projections used in the fourth IPCC assessment (CMIP3). With these projections we force a regionalized glacier mass balance model, and estimate changes in the basins' glacier extent as a function of the glacier size distribution in the basins and projected temperature and precipitation. This glacier mass balance model is specifically developed for implementation in large scale hydrological models, where the spatial resolution does not allow for simulating individual glaciers and data scarcity is an issue. Although the CMIP5 ensemble results in greater regional warming than the CMIP3 ensemble and the range in projections for temperature as well as precipitation is wider for the CMIP5 than for the CMIP3, the spread in projections of future glacier extent in Central Asia is similar for both ensembles. This is because differences in temperature rise are small during periods of maximum melt (July–September) while differences in precipitation change are small during the period of maximum accumulation (October–February). However, the model uncertainty due to parameter uncertainty is high, and has roughly the same importance as uncertainty in the climate projections. Uncertainty about the size of the decline in glacier extent remains large, making estimates of future Central Asian glacier evolution and downstream water availability uncertain.


2011 ◽  
Vol 2 (2-3) ◽  
pp. 106-122 ◽  
Author(s):  
Christof Schneider ◽  
Martina Flörke ◽  
Gertjan Geerling ◽  
Harm Duel ◽  
Mateusz Grygoruk ◽  
...  

In the future, climate change may severely alter flood patterns over large regional scales. Consequently, besides other anthropogenic factors, climate change represents a potential threat to river ecosystems. The aim of this study is to evaluate the effect of climate change on floodplain inundation for important floodplain wetlands in Europe and to place these results in an ecological context. This work is performed within the Water Scenarios for Europe and Neighbouring States (SCENES) project considering three different climate change projections for the 2050s. The global scale hydrological model WaterGAP is applied to simulate current and future river discharges that are then used to: (i) estimate bankfull flow conditions, (ii) determine three different inundation parameters, and (iii) evaluate the hydrological consequences and their relation to ecology. Results of this study indicate that in snow-affected catchments (e.g. in Central and Eastern Europe) inundation may appear earlier in the year. Duration and volume of inundation are expected to decrease. This will lead to a reduction in habitat for fish, vertebrates, water birds and floodplain-specific vegetation causing a loss in biodiversity, floodplain productivity and fish production. Contradictory results occur in Spain, France, Southern England and the Benelux countries. This reflects the uncertainties of current climate modelling for specific seasons.


2017 ◽  
Vol 53 (4) ◽  
pp. 3146-3178 ◽  
Author(s):  
Baohong Ding ◽  
Kun Yang ◽  
Wei Yang ◽  
Xiaobo He ◽  
Yingying Chen ◽  
...  

2007 ◽  
Vol 46 ◽  
pp. 283-290 ◽  
Author(s):  
Jing Zhang ◽  
Uma S. Bhatt ◽  
Wendell V. Tangborn ◽  
Craig S. Lingle

AbstractThe response of glaciers to changing climate is explored with an atmosphere/glacier hierarchical modeling approach, in which global simulations are downscaled with an Arctic MM5 regional model which provides temperature and precipitation inputs to a glacier mass-balance model. The mass balances of Hubbard and Bering Glaciers, south-central Alaska, USA, are simulated for October 1994–September 2004. The comparisons of the mass-balance simulations using dynamically-downscaled vs observed temperature and precipitation data are in reasonably good agreement, when calibration is used to minimize systematic biases in the MM5 downscalings. The responses of the Hubbard (a large tidewater glacier) and Bering (a large surge-type glacier) mass balances to the future climate scenario CCSM3 A1B, a ‘middle-of-the-road’ future climate in which fossil and non-fossil fuels are assumed to be used in balance, are also investigated for the period October 2010–September 2018. Hubbard and Bering Glaciers are projected to have increased accumulation, particularly on the upper glaciers, and greater ablation, particularly on the lower glaciers. The annual net balance for the entire Bering Glacier is projected to be significantly more negative, on average (–2.0ma–1w.e., compared to –1.3ma–1w.e. during the hindcast), and for the entire Hubbard Glacier somewhat less positive (0.3ma–1w.e. compared to 0.4 ma–1w.e. during the hindcast). The Hubbard Glacier mass balances include an estimated iceberg calving flux of 6.5 km3 a–1, which is assumed to remain constant.


1997 ◽  
Vol 43 (144) ◽  
pp. 321-327 ◽  
Author(s):  
Tómas Jóhannesson

AbstractA degree-day glacier mass-balance model is coupled to a dynamic glacier model for temperate glaciers. The model is calibrated for two outlet glaciers from the Hofsjökull ice cap in central Iceland. It is forced with a climate scenario that has recently been defined for the Nordic countries for the purpose of outlining the hydrological consequences of future greenhouse warming. The scenario for Iceland specifies a warming rate of 0.25°C per decade in mid-summer and 0.35°C per decade in mid-winter with a sinusoidal variation through the year. The volume of the glaciers is predicted to decrease by approximately 40% over the next century, and the glaciers essentially disappear during the next 200 years. Runoff from the area that is presently covered by the glaciers is predicted to increase by approximately 0.5 m a−1 30 years from now due to the reduction in the volume of the glaciers. The runoff increase reaches a flat maximum of 1.5–2.0 m a−1 100–150 years from now and levels off after that. The predicted runoff increase leads to a significant increase in the discharge of rivers fed by meltwater from the outlet glaciers of the ice cap and may have important consequences for the operation and planning of hydroelectric power plants in Iceland.


2013 ◽  
Vol 79 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Barbara M. Heyman ◽  
Jakob Heyman ◽  
Thomas Fickert ◽  
Jonathan M. Harbor

AbstractDuring the last glacial maximum (LGM), glaciers existed in scattered mountainous locations in central Europe between the major ice masses of Fennoscandia and the Alps. A positive degree-day glacier mass-balance model is used to constrain paleo-climate conditions associated with reconstructed LGM glacier extents of four central European upland regions: the Vosges Mountains, the Black Forest, the Bavarian Forest, and the Giant Mountains. With reduced precipitation (25–75%), reflecting a drier LGM climate, the modeling yields temperature depressions of 8–15°C. To reproduce past glaciers more severe cooling is required in the west than in the east, indicating a strong west–east temperature anomaly gradient.


2017 ◽  
Vol 63 (240) ◽  
pp. 618-628 ◽  
Author(s):  
MARKUS ENGELHARDT ◽  
AL. RAMANATHAN ◽  
TRUDE EIDHAMMER ◽  
PANKAJ KUMAR ◽  
OSKAR LANDGREN ◽  
...  

ABSTRACTGlacier mass balance and runoff are simulated from 1955 to 2014 for the catchment (46% glacier cover) containing Chhota Shigri Glacier (Western Himalaya) using gridded data from three regional climate models: (1) the Rossby Centre regional atmospheric climate model v.4 (RCA4); (2) the REgional atmosphere MOdel (REMO); and (3) the Weather Research and Forecasting Model (WRF). The input data are downscaled to the simulation grid (300 m) and calibrated with point measurements of temperature and precipitation. Additional input is daily potential global radiation calculated using a DEM at a resolution of 30 m. The mass-balance model calculates daily snow accumulation, melt and runoff. The model parameters are calibrated with available mass-balance measurements and results are validated with geodetic measurements, other mass-balance model results and run-off measurements. Simulated annual mass balances slightly decreased from −0.3 m w.e. a−1 (1955–99) to −0.6 m w.e. a−1 for 2000–14. For the same periods, mean runoff increased from 2.0 m3 s−1 (1955–99) to 2.4 m3 s−1 (2000–14) with glacier melt contributing about one-third to the runoff. Monthly runoff increases are greatest in July, due to both increased snow and glacier melt, whereas slightly decreased snowmelt in August and September was more than compensated by increased glacier melt.


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